<select id="filiere">
    <option>...</option>
{% for choise in filieres %}
    <option value="{{choise.id}}">{{choise.designation}}</option>
        {% endfor %}
</select>
<script>
    $('#filiere').change(function() {
        $.ajax({
            url: '{{path('show_emploi_filiere')}}',
            data: 'id='+$('#filiere').val(),
            success: function(data){
                $('#show_emploi').html(data)
            }
        })
        
    })
        
       
    </script>